Abstract: Process for production of derivatives of 1,3,2-oxazaphosphorinane of general formula 1, ##STR1## wherein R.sub.1 and R.sub.2 represent hydrogen atom or 2-halogenoalkyl group, and R.sub.1 and R.sub.2 are not at the same time hydrogen atoms, and X represents halogen atom is based, according to the invention, on the reduction of the respective 3-halogenoacyl derivatives of 1,3,2-oxazaphosphorinane of general formula 2, ##STR2## wherein the substituents have the above given meaning. The reduction is accomplished with the use of sodium borohydride in the presence of boron trifluoride etherate.Derivatives that are prepared by the procedure described here demonstrate antitumor activity.